Are you talking about these blue-gray lines around the arrow?
I don't know what app I'm looking at here or anything so to see if it's in the msstyle do this:
Use the Color Replacer tool in WSB and replace rgb(12,37,49) with something else and see if it changes.
If it changes then you know it's not an image. Undo the change, then do a color search and start changing locations of the color until you find the right one.
If it doesn't change then you know it is an image. Do a color search including images and start changing locations of the color until you find the right one.
If none of this works then you know the color isn't in the msstyle but in the app itself